Ceramic Onlay Series: 3 of 4 | Porcelain Treatment Protocol for Bonding

Ever wondered what it’s like to see dentistry performed through the lens of a surgical operating microscope?

In this 24 post series, I take you along with me through the entire process of performing an Onlay (partial crown) on Molar Tooth No 3.

We will cover:
 

• Onlay Preparation & Immediate Dentin Sealing

• Tooth Treatment Protocol for Bonding

• **Porcelain Treatment Protocol for Bonding** [This Video]

• Bonding of Ceramic to Tooth Protocol

This segment highlights the porcelain surface treatment in preparation for bonding the porcelain onlay to the tooth.

The tooth has been treated for bonding to the step of primer application. While the porcelain surface is being treated, the solvent has ample time to fully evaporate.

When the lab sends us any porcelain, they have already treated it for bonding. However, that surface is only active for a limited time. If more than 72 hours have elapsed since the lab has treated the porcelain, or if it is “contacted,” as Dr. Jeff Brucia likes to say, (ie. tried on the models,) it loses its optimal bonding capacity as the surface is now damaged!

So what do you do? We certainly want to be the last person to touch the tooth being treated. The last thing anyone wants is for the porcelain to dislodge.

The best course of action is to establish a fresh start. To that effect, the following steps are taken:
 

•  The porcelain is air abraded with GLASS BEADS as it is the kindest medium. We don’t utilize any rocks (ie aluminum oxide, Siljet, Cojet, etc.) as they are too rough and will introduce micro-fractures in the porcelain.
   

•  Next, we acid etch with buffered Hydrofluoric Acid (HF). In the case of lithium disilicate (IPS e-max), we wait 20 seconds.
   

• Now the porcelain surface looks frosty white. Salts have been formed by the HF reaction and should be removed. Utilizing phosphoric acid is a good option. Apply and rub with a micro brush.
   

• The surface now looks less frosty and is ready to be salinated. I like to use the two-bottle system from @Biscodental you can hydrolyze it chair-side. THIS STAGE IS BEST DONE UNDER HEAT (the Calset warmer from @addent_inc is a good option.) Super saturate until the porcelain no longer absorbs silane. Keep it in the heat for full evaporation.
   

• The porcelain surface now looks shiny and is ready for bonding. Let it cool, apply the adhesive from your bond system (a fourth-generation such as Optibond FL from @kavokerr ) and protect from ambient light.

The joy of dentistry…one tooth at a time!